Stephanie,
Maybe they don't have a truck and they need to rent one of hire a mover to do the job! Then I assume, $400 isn't exaggerated!
Unless it was to somebody I know, I wouldn't consider delivering anything to a stranger by fear of not being paid for whatever reason the buyer might find, being held responsible of any damage made to the appliance or to the owner's property and even if I do have a truck, I'd still need to pay someone else to assist me moving a 40" range!
At least, the asking price of $100 is fair for anyone with the ability to move it!